Jason Day and Shane Lowry are the latest big name golfers to withdraw from this summer's Olympics Games in Rio.
World No 1 Day and recent US Open runner-up Lowry have decided not to travel to Rio for the 72-hole event in August.
Both players admit feeling concerned over the Zika virus which has swept through Brazil in recent months.
The mosquito-borne virus has been linked to severe birth defects, which has been a particular concern among golfers.
"The reason for my decision is my concerns about the possible transmission of the Zika virus and the potential risks that it may present to my wife's future pregnancies and to future members of our family," Day said in a statement posted on Twitter.
"I have always placed my family in front of everything else in my life."
The 28-year-old Australian and his wife, Ellie, had their second child in November, and Day has said they want more children.
Meanwhile, newly-married Lowry says he has been monitoring the situation in recent months and used Twitter to reveal: "It is with a very heavy heart I have made the decision to withdraw.
"Wendy and I hope to be lucky enough to have a family in the near future. I have received firm medical advice that I should not travel to Rio this summer.
"I have not taken this decision lightly and it has been a source of much anguish over the past week."
Last week, four-time major winner Rory McIlroy announced he would not play in Rio when golf returns to the Olympics for the first time in over 100 years.
Adam Scott, Louis Oosthuizen, Charl Schwartzel, Marc Leishman and Vijay Singh are other high-profile golfers that have already withdrawn from the Games, which are due to get underway with the Opening Ceremony on Friday, August 5.
Outside of golf, only a handful of athletes have withdrawn from the Olympics. American cyclist Tejay van Garderen cited Zika as his reason for not going to Rio, and NBA star Steph Curry hinted at "other factors" for his decision to skip the Games.
However, Masters champion Danny Willett has confirmed he intends to compete for a medal this year: "The only reason you wouldn't go would be because of concerns about Zika.
"I've spoken to Nicola (wife) about it a lot, and we have concerns, but I'm still down for it and I still want to play.
"The threat is lowering every week. It's come down by half in the last two months."
The International Olympic Committee has resisted calls to move the Games after consultation with the World Health Organisation.